Incidence of cerebral desaturation events in the ICU following cardiac surgery
© Greenberg et al. 2011
Published: 1 March 2011
We hypothesize that there is a high incidence of cerebral desaturation events (CDE - an absolute decrease in SctO2 to <55% for ≥15 seconds) during the first 6 hours of ICU admission following cardiac surgery. Clinical trials have validated transcranial cerebral oximetry, a non-invasive tool that uses near-infrared spectroscopy to measure cerebral oxygen saturation, as a way to detect cerebral ischemia . Cerebral oximetry is frequently used in the intraoperative setting, but rarely utilized postoperatively . We attempted to identify if CDEs occur in the ICU.
This IRB-approved, prospective, observational study captures the CDE incidence from 40 ASA IV patients in the ICU period following elective cardiac surgery. Exclusion criteria were: age <18, patients presenting for emergency surgery, and patients undergoing off-pump procedures. The FORE-SIGHT (CAS Medical Systems Inc., Branford, CT, USA) absolute cerebral oximeter monitor remained on patients for the first 6 hours in the ICU. All patients were managed according to the usual ICU standard of care. All care providers were blinded to CDEs during the 6-hour study period. During this time, a portable computer was attached to the cerebral oximeter, bedside physiologic monitor and mechanical ventilator, which recorded all data at 1-minute intervals and allowed data to be stored on a computer database.
Complete data were collected on 40 high-risk patients (mean age of patients = 71 (36 to 86), mean duration of intubation (hours) = 22.8 (6 to 240), mean duration of ICU stay (days) = 3.3 (1 to 20)). A majority of the patients underwent coronary bypass grafting only or valve only procedures. A high incidence, 13/40 (32.5%), of CDEs was observed in our study cohort, with some episodes exceeding 2 hours. A higher incidence of postoperative nausea/vomiting (PONV) was observed in patients with CDEs (3/13 vs. 0/27).
This observational trial is the first to demonstrate a high incidence of CDEs in the immediate postoperative period (32.5%) among cardiac surgical patients. Our ongoing observational study will attempt to demonstrate correlations between physiologic parameters and these postoperative CDEs.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.